Update static URL rewrite rule to use QSA flag

Using the QSA flag in the RewriteRule will allow parameters to be passed down to the rewritten URL. One use case for this is when using Xdebug's profiler trigger. It makes it possible so that http://mage2.dev/pub/static/frontend/Magento/blank/en_US/mage/calendar.css?XDEBUG_PROFILE=1 will generate the profile file otherwise the XDEBUG_PROFILE parameter is essentially ignored.